This invention relates to electrolytes and more particularly, electrolytes for use in electrochemical sensors.
For many years, electrochemical sensors have been used to measure the concentration of certain gases. Typically, such sensors include a cell having two or more electrodes separated by an electrolyte. In the presence of an oxidizable gas, an oxidation-reduction reaction takes place within the cell, creating a sensor output signal in the form of a current flow between the electrodes. The magnitude of the current is a measure of the concentration of the gas.
Many prior art electrochemical sensors employ liquid electrolytes, which are easy to prepare and are highly conductive. However, because these sensors must be designed to prevent leakage of the electrolyte, they are generally larger and heavier than sensors employing non-liquid electrolytes. The liquid electrolyte sensors also tend to be position-sensitive.
Some prior art electrochemical sensors employ solid electrolytes in their construction. These electrolytes are generally prepared from commercially manufactured solid chemicals, and permit the construction of small, lightweight sensors. It has been found, however, that gas sensors using these solid electrolytes generally produce output signals which are not linearly related to measured gas concentration, and which vary significantly as a function of ambient temperature. Accordingly, such sensors are not highly accurate, and require compensation circuitry for their use.
Still other prior art electrochemical sensors employ gelled electrolytes which do not suffer from the position sensitivity of liquid electrolytes. Gelled electrolytes can also be used over a wider range of temperatures and pressures than can liquid electrolytes. However, a major disadvantage of using gelled electrolytes is the tendancy of the liquid in the electrolyte to evaporate, causing the gel to shrink. Such shrinking produces erratic and unreliable sensor performance.
Accordingly, it is an object of the present invention to provide a new and improved electrolyte for use in electrochemical sensors.
It is another object of the present invention to provide a powdered liquid electrolyte for use in electrochemical sensors.
It is yet another object of the present invention to provide an electrochemical sensor using a powdered liquid electrolyte.